Epsilon Data Management, Experian and LexisNexis said they would continue to cooperate with the Senate committee. Acxiom declined to comment. Medbase200 didn’t respond to requests for comment.

Ethnic Technologies LLC provides lists with ethnic and religious groupings, including Americans broken out by race who don’t use mainstream financial services, according to its website. The site said its customers include banks, home-mortgage lenders and credit-card companies. The company didn’t return calls seeking comment.

Exact Data ConsumerBase LLC, a provider of direct-marketing services, on its website has consumer lists such as “Americans with Student Loan Debt” and “Bankrupt Consumers in Dallas.” The company didn’t return a call seeking comment.